title: Alternative complement pathway-dependent ingestion of fluolite particles by human granulocytes.
abstract: Fluorescent particles (Fluolite) with an average size of 0.1 micrometers were ingested by human granulocytes after incubation in fresh normal human serum (NHS). Ingestion was assessed by visual counting in a fluorescent microscope of cells containing particles. Ingestion required fresh normal serum and did not occur when serum was heated for 30 min at 50 degrees C or in the presence of ethylenediaminetetraacetic acid (EDTA). It did not occur in serum genetically deficient in C3b inactivator or in C3. Phagocytic activity was restored to C3-deficient serum by purified human C3 and to heat inactivated serum by purified factor B. Opsonic activity was present in NHS containing 5 mM Mg++ and 10 mM ethyleneglycoltetraacetic acid (EGTA) and in human serum genetically deficient in human C components C2 and C5. Agammaglobulinemic sera had normal opsonic activity. Opsonization of particles in this system is mediated through the alternative pathway of C activation, and its measurement serves as a simple quantitative functional assay for this system.
mesh_terms: D003167:Complement Activation; D003175:Complement C2 / Q000172:deficiency; D003176:Complement C3 / Q000172:deficiency; D003180:Complement C3b Inactivator Proteins / Q000172:deficiency; D003182:Complement C5 / Q000172:deficiency; D003170:Complement Pathway, Alternative; D004492:Edetic Acid / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D005456:Fluorescent Dyes; D006098:Granulocytes / Q000276:immunology*; D006801:Humans; D008863:Microspheres; D009895:Opsonin Proteins; D009930:Organic Chemicals; D010587:Phagocytosis
chemical_list: D003175:Complement C2; D003176:Complement C3; D003180:Complement C3b Inactivator Proteins; D003182:Complement C5; D005456:Fluorescent Dyes; D009895:Opsonin Proteins; D009930:Organic Chemicals; D004533:Egtazic Acid; C030727:fluolite particles; D004492:Edetic Acid